Latent holographic media and method

Abstract

A holographic recording medium having a polymer matrix comprising a developer, wherein the holographic recording medium is capable of recording a latent hologram and the developer is capable of developing the latent hologram into a readable hologram by activation of the developer is disclosed. The holographic recording medium is capable of storing large numbers of holograms in the same volume with better signal resolution than previous holographic media by first recording a multitude of latent (or very weak) holograms in the same volume of space, then applying preferably a non-chemical fixing step to develop the latent holograms into readable holograms. The holographic recording medium and method of this invention cause the holograms to increase in diffraction efficiency, thus preventing complications caused during recording of holograms whereby previously recorded holograms interfere with latter recorded holograms in the same volume of space within the media.

Description

FIELD OF THE INVENTION[0001]The invention relates to latent holographic recording medium and a method for manufacturing the same. In addition the invention relates to the precursors, particularly fast reaction precursor system for manufacturing latent holographic recording medium. The use of latent holographic medium and the precursors includes holographic optical data storage, optical lenses, beam steerers, and waveguides.BACKGROUND[0002]Developers of information storage devices and methods continue to seek increased storage capacity. As parts of this development, so-called page-wise memory systems, in particular holographic systems, have been suggested as alternatives to conventional memory devices.[0003]In the typical holographic storage system, two coherent light beams are directed onto a storage medium. The first coherent light beam is a signal beam, which is used to encode data. The second coherent light beam is a reference light beam. The two coherent light beams intersect wi...

AI Technical Summary

Benefits of technology

This patent describes a new type of holographic recording media that can store more holograms in the same space with better signal resolution. The media works by first recording a lot of weak holograms in the same area, and then applying a non-chemical step that makes the holograms more efficient at diffraction. This prevents previous holograms from interfering with later ones in the same space, resulting in a more complex and complete recording.

Problems solved by technology

These were still photosensitive and limited the life of the developed emulsion.

However, silver halide materials were found to lack high dynamic range (ability to store data), had poor archival stability, and were difficult to work with because of the chemical processing needed to develop and fix the holograms.

However, the ability of the photopolymer class of holographic media to self develop does result in a problem when large numbers of holograms are recorded into the same volume (which is required for high density data storage).

Thus, as more and more holograms are written to the same volume of space, a very complex pattern of spatial refractive index is created within the photopolymer matrix.

This spatial inhomogeneity (or modulation) causes the later writing beams to diffract, creating undesired optical noise that in turn writes undesired modulation components into the photosensitive medium, e.g., the photopolymer matrix.

This recording of secondary diffracted light can be a significant cause of signal degradation, and therefore, diminished storage density.

Furthermore, light diffracted from the secondary modulation will record tertiary modulation and so on, so that many orders of rediffracted noise light are created and recorded.

In short, the capabilities of holographic storage systems are limited in part by the storage media.

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